Accumulative impacting head for nut runners and the like



Ma, 4 1948. N. E. SIMS, JR 2,440,834

ACCUMULATIVE IMPACTING HEAD FOR NUT RUNNERS AND THE LIKE Filed Dec. 28, 1946 Patented M ys;

I Norman E. Sims, Jra Arlington, Va. Application her 28, 1946, Serial No. 118.994

h (Cl. 192-405) This invention relates to improvements in nut runners and similar appliances.

in conventional nut runners a spring-loaded clutch is generally interposed between the tool spindle and the motor drive so that the clutch laws remain in engagement, permitting the nut or screw to be turned through the torque of the the rollowing description of a practical embodiment of the invention proceeds.

In the drawings whichaccompanypnd form a part of the specification, and throufi'hout the motor until a critical point is reached. at which the resistance of the not or screw overcomes the spring, causinfs intermittent slipping and reenaagement of the clutch. producing a series of impact blows between the clutch jaws, rotatively hammering the nut or screw to its final 'ition oi tightness.

Since in the conventional nut runner the clutch spring always releases at the same level of resistance,.-the impact blows are of substantially constant force. it v hermore, the motor must be powerful enough to develop a torque that will keep the nut or screw turbine: up to the point at which the, clutch spring yields and the impact action starts.

one of the objects of the present invention is to provide a nut er in which the clutch functions as such only to provide a "dead" tool spindle while the motor is running, to permit the tool to be applied to the nut, the clutch incorporating means for resolving the torque of the motor into a succession of rapid impact blows effective from the beginning of the not running operation, the force of said blows being directly proportional to the resistance encountered, and therefore being slight at the beginning of the screwing. movement and building up progressively to the magnitude required tor the final tightenins phase.

Another object oi the invention is to provide a nut runner oi the type described, in which each impact blow is the resultant oi two force components, one being the torque of the driving means, and the other-the reaction component of the immediately preceding impact blow.

A further object of the invention is to provide a nut runner in which the tool spindle carries a series of anvils and the driving means a rotor carrying a plurality of hammers enaageable with said anvils for striking successive impact blows thereagainst to turn the spindle, with means for transferring the reaction component of each impact to the torque component of the next succeeding impact, whereby the blows oi the ham-- Other objects of the invention will appear as several figures of which the same reference characters have been employed to denote identical parts:

Figure l is a longitudinal sectional view through a nut runner. incorporating the principles of the invention, the tool spindle being shown declutched 'irom the drive;

Figure 2 is a side elevation of the rotary hammer carrier;

Figure 3 is a section taken along the line 3-3 oi Figure l:

Figure 4 is a diagrammatic view showing one of the hammers in striking position with respect to an anvil;

Figure 5 is a similar view in recoil position;

Figure 6 is, a view in end elevation of the hammer carrier, showing the parts in neutral position.

Referring now in detail to the several figures, the numeral i represents a casing preferably made in three parts, t, d and d, suitably secured together as by the bolts 6. with a partition plate 8, which functions as a bearing support, being between the parts 3 and t and clamped by said bolts. The casing part 2 contains a reversible electric motor, not shown, controlled by a switch t, which is mounted on the outside of the easing. The part 3 houses a train of reduction gears ii, and is formed with a partition to, con stituting a bearing support, and the part 4 en-- closes the hammer and anvil mechanism H, which embodies the concept of the present invention, said part d having a reduced end portion 92, which affords a housing and support for the yieldably mounted tool spindle i3. The latter, as shown, has a. removable nut socket. i2",

showing the hammer the device is designed to operate.

The hammer-mechanism comprises a rotatable carrier it, including a shaft i5, and a diametrical plate It centered on said shaft at one end, the face of the plate It remote from the shaft having diametrically disposed projecting bearing bosses i1 and I 8 on opposite sides of the axial center of the plate [6, equidistant from said center and axially parallel to the axis of the shaft I 5. Said shaft has extreme portions i 9 and 20 journaled in bearings in the partition plate 8 and the partition Ill, and an intermediate portion 2|, which extends through the ano es final gear 22 of the reduction train and is secured thereto. The shafts II and spindle I 8 are coaxial.

Apair of intermeshing gears 28 and 24, of the same size, are freely iournaled on the respective bosses I1 and i8. These necessarily turn in reverse directions when rotated. Each carries on its outer face an arcuate hammer, the respective hammers being designated by the numerals 25 and 28. These have radial end faces, as shown, the hammers extending over an arc of one quadrant. The gears 28 and 24 are so meshed as to place the hammers in such phase relation that in one position of the gears the hammers are as shown in Figure 42, occupying opposite quadrants in the upper halves iof the respective gears, with an end face of each coinciding with a line passing through the centers of the gears. The tool spindle i3 is slidable in a bearing 21. At its inner end it is provided with a spider 28, preferably integral therewith, which carries at its ends the anvils 29, 30 and Si, spaced 120 apart. The anvils have radial end faces. The spindle i3 has an adjustable collar nut 32, screwed upon a threaded zone of said spindle and slidable within a counterbore in the reduced end of the casing, there being a spring 33 within said counterbore confined under compression between said collar nut and the inner end of the counterbore, an end thrust bearing intervening between said spring and collar nut. The effort of said spring is to bias the tool spindle l8 in an outward direction, keeping the anvils out of the path of rotation ofthe hammers so that the spindle is dead," that is, not rotating. When the nut runnor is pressed against the nut or screw, as the case may be, the spring 33 is compressed, causing the spindle to slide inward to bring the anvils 28, 30 and BI into the plane oi the hammers 25 and 26. I

Provision is made to ensure that one of the hammers shall always be in outermost position in the path of the anvils when the motor is runnin free. With this end in view, one of the gears, for example, the gear 24 in Figure 6, is weighted with lead inserts 34, opposite the hammer 28. to counterbalance said hammer, neutralizing its centrifugal urge to move out in opposition to the weight of the hammer 25. Therefore, under the centrifugal force generated by the free rotation of the hammer carrier l4, the gears will always be in the relative positions shown in Figure 6, with the hammer 26 in outermost position, ready to strike a blow against an adjacent anvil in either direction, as soon as it is brought into the path of the anvils.

Referring now to the mode of operation of the nut runner, and assuming that the motor is running free with the hammer carrier l4 rotating in a counterclockwise direction, as indicated by a the arrows a in the diagrammatic figures, and the gears and hammers being in the centrifugally determined position shown in Figure 6, and that the apparatus is under pressure so that the anvils iii are in the path of the hammer 25, this strikes a blow against the anvil 29. At the beginningof the nut screwing movementrthe nut may oppose but little resistance to being turned, so that the anvil 29 yields readily to the hammer, the impact force being slight, not materially greater than that of the driving torque. But' whatever the impact force may be, the reaction component against the hammer 25 causes said hammer to recoil in a clockwise direction, turning the gear 23 4 in a clockwise direction, imparting counterclockwise rotation to the gear 24 and the hammer 28 carried thereby. The hammers in the recoil position of the hammer 2B are shown in Figure 5. In this Figure the gear 24 is bodily traveling counterclockwise, as indicated by arrow a, and

the hammer 38 is traveling counterclockwise through the rotative impulses imparted to it by the recoil of the hammer 25, so the hammer 2B strikes the anvil 3! a blow. the force of which is the resultant of the torque force of the rotatin hammercarrier augmented by the reaction force transferred from the hammer 25. 4 i

It will be understood from Figure 5 that the hammer as is shown at an intermediate position in its recoil movement, in which it is about to pass below the anvil 29, and that by the time the hammer 26 strikes the "anvil 8i, it will have moved completely out of the path of the anvil 29 and been carried thereunder by the counterclockwise translatory movement of the gear 23. The instant the hammer 28 strikes the anvil 3|,lit will recoil under the impact, reversing the dir tion of movement of the gears, so that the ar 23 now moves counterclockwise, driving the hammer 25 against the anvil 30, which hammer is already traveling towards said anvil under the constant circumferential torque of the rotating hammer carrier l4.

Since each impact component derived from the rotation of the hammer carrier is augmented by the reaction component derived from the immediately preceding impact, it follows that the blows progressively increase in intensity proportionately as the load resistance increases, and that they are at all times greater than would be the directly applied torque force. Consequently, a less powerful motor is adequate to carry a given load than if the torque force were directly applied to the load, or solely relied upon to produce impact blows through mere lost motion between the driving and driven parts.

The compound movement of the hammers relative to the anvils resultant from the translatory movement of the gears and the recoil movements of the hammers, through which compound movement each hammer strikes the anvils suc-r cessively, passing beneath the anvil from which it rebounded, may be correctly described as an escapement action.

As shown and described, the hammers each circumscribe a arc, and both have and faces in radial planes. This provides for actuation of the tool spindle in either direction. If the nut runner were designed solely for unidirectional operation, the hammers could be of less arcuate amplitude with only the leading ends, (the striking ends) being in radial planes.

While I have in the above description disclosed what I believe to be a practical embodiment of of the invention, it will be understood by those skilled in the art that the particular application of the inventive principle to a nut runner, and the specific construction and arrangement of the parts, as shown, are to be regarded as illustrative and not to be construed as limiting the scope of the invention.

What I claim as my invention is:

1. Nut runner comprising a tool spindle rotatably mounted, having a radially extended head at one end, a plurality of spaced anvils carried by said head adjacent the periphery thereof at equal radial distances symmetrically about the axis of said spindle and in a common diametrical plane, a 'motor driven plate rotatably mounted a coaxial of ?said spindle, a pair of intermeshing gears moui'ited on said plate freely rotatable about axes perpendicular thereto and equidistant from the axis of rotation of said plate on opposite sides of said axis, and hammers carried by said gears operating between said anvils in the path thereof for converting the torque of said driving means into a succession of impact blows circumferentially againstsaid anvils for rotating said spindle, the impact recoil of one hammer being transferred through said gears to the other hammer to augment the torque-generated impact of said other hammer: r

2. Nut runner comprising a tool spindle rotatably mounted, having a radially extended head at one end, a plurality of spaced anvils carried by said head adjacent the periphery thereof at equal radial distances symmetrically about the axis of said spindle and in a common diametrlcal plane, a motor driven plate rotatably mounted coaxial of said spindle, a pair of intermeshing gears mounted on said plate freely rotatable about axes perpendicular thereto and equidistant from the axis of rotation of said plate on opposite sides of said axis, and hammers carried by said gears projecting from the faces of the respective gears between said anvils and into the path thereof for converting the torque of said driving means into a succession of impact blows circumferentially gainst said anvils for rotating said spindle, the impact recoil of one hammer being transferred through said gears to the other hammer to augment the torque-generated impact of said other hammer.

3. Nut runner comprising a tool spindle rotatably mounted, having a radially extended head at one end, a plurality of spaced anvils carried by said head adjacent the periphery thereof at equal radial distances symmetrically about the axis of said spindle and in a common diametrical plane, a motor driven plate rotatably mounted coaxial of said spindle, a pair of intermeshing gears mounted on said plate freely rotatable about axes perpendicular thereto and equidistant from the axis of rotation of said plate on opposite sides of said axis, and hammers carried by said gears projecting from the faces of the respective gears between said anvils, into the path thereof, of less circumferential length than the space between said anvils, for converting the torque of said driving means into a succession of impact blows circumferentially against said anvils for rotating said spindle, the impact recoil of one hammer being transferred through said gears to the other hammer to augment the torque-generated impact of said other hammer.

4. Nut runner comprising a tool spindle rotatably mounted, having a radially extended head at one end, three spaced anvils carried by said head adjacent the periphery thereof at equal radial distances symmetrically about the axis of said spindle and in the same diametrical plane, a motor driven plate rotatably mounted coaxial of said spindle, a. pair 01' intermeshing gears mounted on said plate freely rotatable about axes perpendicular thereto and equidistant from the axis of rotation of said plate on opposite sides of said axis, and a hammer carried by each gear, said hammers operating between said anvils in the path thereof and being of less circumferential relative phase that ing movable into spindle, a pair iierential length 6 through said gears to the other hammer to augment the torque-generated impact of said other hammer, said hammers being arranged in such when one is at the maximum distance from the axis of rotation of said plate. the other is at the minimum axis, whereby through the compound movement produced by the rotation torque the recoil-produced movement of said ham-mere. each strikes successive anvils, escaping beneath the anvil last struck.

5. Nut runner comprising a tool spindle rotatably mounted. having a radially extended head at one end, a plurality of spaced anvils carried by said head adjacent the periphery thereof at equal radial distances tor driven plate rotatably mounted coaxial of said spindle, a pair of intermeshing gears mounted on said plate freely rotatable about axes perpendicular thereto and equidistant from the axis of rotation of said plate on opposite sides of said axis. and hammers carried by said gears projecting toward said anvils and being of less circumferential length than the space between said anvils,

driving means axially apart whereby said driving means can normally rotate independently of the path of said anvils under axial pressure applied contra to said spring means, into driving relation to said torque of said driving means is converted into a succession of impact blows circumferentially against said anvils, the impact recoil of one hammer being transferred through said gears to the other hammer to augment the torque-generated impact of said other hammer.

a Nut runner comprising a tool spindle rotatably mounted, having a radially extended head at one end, three head adjacent the periphery thereof at equal symmetrically about the axis of of intermeshing gears mounted on said plate freely rotatable about axes perpendicular thereto and equidistant from the axis of rotation of said plate on opposite sides of said axis, and hammers carried by said gears projecting toward said anvils and being of less circumthan the space between said anvils, spring means for normally biasing said tool spindle and driving means axially apart whereby said driving means can normally rotate independently of said spindle, said hammers being movable into the path of said anvils under axial pressure applied contra to said spring means whereby the torque of said driving means is converted into a succession of impact blows circumfelentially against said anvils, the impact recoil of one hammer being transferred through said gears to the other hammer, to augment the torque-generated impact of said other hammer,

said hammers being arranged in such relative length than the space between said anvils for phase that when one is at the maximum distance from the axis of rotation of said plate, the other is at the minimum distance from said axis,

whereby through the compound movement produced by the rotation torque of said plate and the recoil-produced movement of said hammers, each strikes successive anvils, escaping beneath the anvil last struck.-

distance from said.

of said plate and ring means for normally biasing said' tool spindle and said spindle, said hammers bespindle whereby the spaced anvils carried by said 7. Nut runner comprising a tool spindle rotatably mounted. havina anvil means at one end radially oii'set from the axis oi. rotation. a motor drive for said spindle comprising a motor driven plate rotatably'mounted coaxial of said spindle. apair of intermeshingsgears mounted on said plate freely rotatable about axes parallel to the common axis oi rotation of said spindle and plate, equidistant irom said axis on opposite sides thereof, a hammer projecting from each gear toward said anvil means, said hammers being arranged in such relative phase that when one is atthe maximum distanceirom the axis of rotation of said plate the other is at the minimum distance. the radius oi rotation of said hammers when at said maximum distance beins equal to the radius 01' rotation of said anvil means, spring means normally biasing said anvil means and motor driven plate axially apart whereby said plate can normally rotate independently of said spindle. said hammers being movable into the zone of said anvil means under axial pressure applied contra to said spring means, one said gears being provided'with means for counterbalancing the weight oi the hammer of that gear, nulliiying the centrifugal moment of that hammer whereby the unbalanced weight 01 the other hammer causes it to assume and maintain a position at maximum distance from the axis or rotation of said-plate when said plate is running free. in position to strike said anvil means when in the zone 01' said means in either direction of rotation of said plate.

8. Escapement means comprising a rotor including a pair of intermeshing gears freely rotatable about axes parallel to the axis 01' rotation oi. said rotor and equidistant from said axis on opposite sides thereoi, spaced anvils, means supporting said anvils, maintaining them at equal radial distances symmetrically about the produced axis of said rotor and in a common diametrical plane. a hammer projecting from each gear into the zone of said anvils. said hammers being 01 less circumierential extent than the space between said anvils and being arranged in such relative p ase that when one is at the maximum distance om the axis of rotation of said rotor-the other i at the minimum distance from said axis, said maximum' distance being equal to the radial distance.

of said anvils from said produced axis, whereby through the compound movement of said hammers produced by the rotation torque of said rotor and the recoil-produced movement of said hammers, each strikes successive anvils, escaping beneath the anvil last struck.

NORMANE, SIMS, J a.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Name Date Decker Aug. 30, 1932 Levedahl Oct. 11, 1932 Pott Aug. 27, 1935 Hutchinson Dec. 24, 1940 Number 

